CA2035740C - Method for determining air mass in a crankcase scavenged two-stroke engine - Google Patents
Method for determining air mass in a crankcase scavenged two-stroke engineInfo
- Publication number
- CA2035740C CA2035740C CA002035740A CA2035740A CA2035740C CA 2035740 C CA2035740 C CA 2035740C CA 002035740 A CA002035740 A CA 002035740A CA 2035740 A CA2035740 A CA 2035740A CA 2035740 C CA2035740 C CA 2035740C
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- Prior art keywords
- air
- crankcase
- mass
- chamber
- engine
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- 238000000034 method Methods 0.000 title claims abstract description 25
- 238000002485 combustion reaction Methods 0.000 claims abstract description 44
- 238000012546 transfer Methods 0.000 claims abstract description 12
- 230000006870 function Effects 0.000 description 14
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 10
- 239000000446 fuel Substances 0.000 description 10
- 238000012937 correction Methods 0.000 description 7
- 235000014676 Phragmites communis Nutrition 0.000 description 6
- 230000006835 compression Effects 0.000 description 6
- 238000007906 compression Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 3
- 238000012935 Averaging Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 101100536354 Drosophila melanogaster tant gene Proteins 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000012886 linear function Methods 0.000 description 1
- 238000012417 linear regression Methods 0.000 description 1
- 101150108859 maeB gene Proteins 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000000545 stagnation point adsorption reflectometry Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/76—Devices for measuring mass flow of a fluid or a fluent solid material
- G01F1/86—Indirect mass flowmeters, e.g. measuring volume flow and density, temperature or pressure
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/18—Circuit arrangements for generating control signals by measuring intake air flow
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/30—Controlling fuel injection
- F02D41/32—Controlling fuel injection of the low pressure type
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/02—Engines characterised by their cycles, e.g. six-stroke
- F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
- F02B2075/025—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle two
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D2400/00—Control systems adapted for specific engine types; Special features of engine control systems not otherwise provided for; Power supply, connectors or cabling for engine control systems
- F02D2400/04—Two-stroke combustion engines with electronic control
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Testing Of Engines (AREA)
Abstract
METHOD FOR DETERMINING AIR MASS IN A
CRANKCASE SCAVENGED TWO-STROKE ENGINE
Abstract of the Disclosure A method is described for determining the cylinder mass of air available for combustion in a crankcase scavenged, two-cycle engine, based upon the Ideal Gas Law relationship and indications of pressure, volume, and temperature of air in the crankcase chamber, at predetermined points in the engine operating cycle. This is achieved by first determining the mass of air trapped and compressed in a crankcase chamber, and thereafter, determining the residual air mass remaining in the crankcase after the transfer of air to the associated combustion chamber. Then, the actual air mass transferred to the combustion chamber is determined as a function of the difference between the trapped and residual air masses. Engine trapping efficiency can be used to correct for air leakage from the combustion chamber prior to cylinder exhaust port closure. The volume of the air within the crankcase chamber is derived as a function of engine cycle position, with crankcase air temperature being derived as a function of intake air temperature. Air pressure in the crankcase is monitored with a pressure transducer.
CRANKCASE SCAVENGED TWO-STROKE ENGINE
Abstract of the Disclosure A method is described for determining the cylinder mass of air available for combustion in a crankcase scavenged, two-cycle engine, based upon the Ideal Gas Law relationship and indications of pressure, volume, and temperature of air in the crankcase chamber, at predetermined points in the engine operating cycle. This is achieved by first determining the mass of air trapped and compressed in a crankcase chamber, and thereafter, determining the residual air mass remaining in the crankcase after the transfer of air to the associated combustion chamber. Then, the actual air mass transferred to the combustion chamber is determined as a function of the difference between the trapped and residual air masses. Engine trapping efficiency can be used to correct for air leakage from the combustion chamber prior to cylinder exhaust port closure. The volume of the air within the crankcase chamber is derived as a function of engine cycle position, with crankcase air temperature being derived as a function of intake air temperature. Air pressure in the crankcase is monitored with a pressure transducer.
Description
203~7~a METHOD FOR DeTERllINING AIR MASS IN A
CRAN~CASE 8CAVI~NGED 1~10--STROI~E ENGINE
Background of the Invention Thi6 invention relate6 to the determination of engine mas6 air-flow and more particularly to a method for deriving an indication of the ma6s sf air available for combu6tion within a cylinder of a crankca6e 6cavenged two~6troke engine In a crankca6e 6cavenged two-6troke engine, each individual cylinder ha6 $t6 own 6eparate crankca6e chamber During portion6 of the engine operating cycle, air i6 inducted into each crankcase chamber, compre6sed while the crankca6e chamber i~ decrea6ing in volume, and then tran6ferred to the a660ciated cylinder combu6tion chamber, where it i6 mixed with fuel for ignition In order to effectively control the emi66ion and performance charactoristic6 of 6uch an engine, it i8 nece6sary to know the mas6 of air available at the time of combustion within each cylinder Once thi6 lnformation 16 known, the air-fuel ratio can be ad~usted accordingly to achieved the de6ired emi~6ion and performance ob~ectives Conventional hot wire or hot film 6ensor6 can be u~ed to ea~ure the total air-flow per cycle, in a two-~troke englne, however, these ~ensors tend to be rel~tlvely xpenslve, fraglle, and easlly contamlnated by dlrt ln the ~lr flow Altern~tlves have been propo~-d for llmlnatlng convontlonal mass air-flow -n~ors ln cr~nkcase ~cavenged, two-~troke engines, and for estlmatlng the lndivldual ma~8 alr-flow per , ': ., .
., , ~ .
cylinder. These techniques are described in copending Can. Application Ser. No. 2012431 filed 16 March 1990, and copending Can. Application Ser. No. 2017523 filed 25 May 1990, assigned to the assignee of this application.
In each case, the mass of air trapped within a crankcase chamber is determined as a function of pressure, volume, and temperature of the air during crankcase compression, prior to the transfer of air to a cylinder combustion chamber. Each technique requires correction factors to account for incomplete transference of air between crankca~e and combustion chambers, and to account for leakage of the transferred air out of the combustion chamber prior to cylinder exhaust port closure.
Summary of the Invention The present invention is directed toward determining the mase of air available for combustion in a cylinder of a crankcase scavenged, two-stroke engine, based upon derived indication~ of the pressure, volume, and temperature of air within the associated crankcase chamber, without requiring a correction for the incomplete transfer of air between the crankcase and combu~tion chamber~. Thi~ i8 accompli~hed by first determining the ma~s of air Mk trapped while undergoing compre~sion in a crankcase chamber, and then determining the residual air ma~s MR remaining in the crankca~e, just after the transfer of air to the combustion chamber. The ma~s of air actually transferred to the combuetion chamber i~ then determined directly as a function of the difference ~M~-M~) between the trapped and residual crankca~e air ma~ses. Accordingly, a correction to account for incomplete air tran~ference between crankcase and ''' ' ' ' ' ' ' ' . ' ' ' 203~7~
combustion chambers is not required. Thus, an important feature of the present invention is that combustion mass air can be accurately determined u~ing only a single correction to account for that amount of air which leaks from the cylinder combustion chamber prior to exhaust port closure.
In accordance with the principle of the invention, air mass within a crankcase, both during crankca6e compres~ion and after the transfer of air to the associated combustion chamber, i~ preferably determined according to the Ideal Gas Law, M - PV/~T, where M, P, V, T, and R, are respectively the mass, pressure, volume, temperature, and gas constant for air within the crankcase, determined at the appropriate time6 during the engine operating cycle. Consequently, crankca6e chamber mass air is computed using a relatively 6imple algebraic relationship requiring low computational overhead in a conventional microproce6sor ba~ed engine control 6ystem.
Further, in the preferred embodiments of the present invention the mass of air transferred to a combustion chamber is equated to the expre6sion a +
~MT ~ M~), a predetermined linear function of the difference between the trapped and residual crankcase alr ma~es. Accordingly, improved accuracy i6 achieved when predicting the tran6ferred air ma6s because values for the con~tant6 a and ~ are selected to corre6pond to a be6t flt llne, which relate6 measured and calculated alr flow data obtained under dlfferent engine operating condltions.
Addltlonally, the present invention provides for derlving a required indication of crankcase air temperature a6 a functlon of the temperature of air , ~03~7~
inducted into the engine. This is accomplished by either assuming that the crankcase air temperature is equal to the intake temperature, or a more accurate functional relationship between the crankcase and intake air temperatures can be used, by assuming that the expansion and compression of crankcase air behaves i6entropically. This i6 a 6ignificant feature since engine temperature 6ensors typically have long lag time6 relative to engine cycle time. As a result, intake air temperature, which is generally slowly varying, can be measured more accurately than crankcase air temperature, which varies rapidly over an engine cycle. Also, means for measuring intake air temperature already exists in most typical engine control sy6tems. Consequently, by deriving crankcaEe air temperature as a function of air intake temperature, the invention generally does not require an additional crankcase temperature sen60r to function properly.
According to another aspect of the invention, crankcase volume is derived a6 a predetermined function of the engine cycle position. Preferably, the volume within a crankcase chamber at a given time is defined by the angular rotation of the engine crankshaft as measured by means already existing in a typical engine control system.
A6 contemplated by another a6pect of the lnvention, the pres6ure of air within a crankcase chamber is preferably derived from a conventional pressure 6ensor, dispo~ed within the crankcase chamber.
As a re6ult, the invention require6 only the addition of a relatively inexpensive pres6ure tran6ducer to a ' .
3 ~ L~
conventional computer engine control ~ystem to enable the determination of the cylinder mass air flow.
According to still another aspect of the invention, the value for the air ma6s transferred from a crankcase chamber to its associated cylinder i~
corrected to account for the amount of air which leak~
out of the cylinder prior to closure of the exhaust port. Thu6, an accurate e6timate for the mass air available for cylinder combustion is achieved.
These and other aspects and advantages of the invention may be best understood by reference to the following detailed description of the preferred embodiments when considered in conjunction with the accompanying drawings.
Descr~tion of the Drawings FIG. 1 is a ~chematic diagram of one cylinder of a crankcase scavenged two-stroke engine and control 6ystem therefore, that includes the system for estimating the mass of air available for combustion in accordance with the principles of this invention; and FIG. 2 i6 a flow diagram representing lnstructions in the routine executed by the computer in FIG. 1, when determining the mas6 of air available for combustion in accordance with the principles of thi~
invention.
Detailed DeE_rlptlon of the Preferred Embodiments Referring to FIG. 1, there is shown schematlcally a crankcase scavenged two-~troke engine, generally de8ignated as 10, with a portion of the englne exterlor cut away, expo~lng cylinder 14. Piston 12 re~ides within the wall of cylinder 14, with rod 16 connecting plston 12 to a rotatable crank6haft, not shown, but dl~posed wlthln crankca6e chamber 18.
, .
~ ~ ' ~35~
Connected to engine 10 is an air intake manifold 20 with a throttle 22, and an exhaust manifold 24.
Cylinder 14 communicates with exhau6t manifold 24 through exhaust port 24 in the wall of cylinder 14.
Intake manifold 20 communicate6 with cylinder 14 and crankca6e chamber 18 through a reed valve checking mechanism 28, which opens into a common air tran6fer pa6sage 30 linking crankcase port 32 with inlet port 34 in the wall of cylinder 14. Cylinder 14 i6 provided with a 6park plug 36 and an electric solenoid driven fuel injector 38 projecting into combustion chamber 40.
A6sociated with engine 10 are variou6 conventional 6en60r6 known to the art, which provide typical ~ignal6 related to engine control. Located within the air intake manifold 20 are a pre66ure sen60r 42 for mea~uring intake manifold absolute pres6ure ~MAP), and a temperature 6ensor 44 for mea~uring manifold air temperature (MAT). Electromagnetic sengors 48 and 50 provide pul~ed ~ignal6 indicative of crankshaft rotational position (ANGLE) and the top dead center po6ition for cylinder 14 tTDC), by re6pectively ~ensing movement of the teeth on ring gear 52 and di6k 54, which are attached to the end of the engine crank6haft. The crank6haft rotational angle ~ from top dead center in cylinder 14 can be obtained by counting the number of pul~e6 occurring in the ANGLE 6ignal ater the TDC pulse, then multiplying that count by the angular spacing of teeth on rlng gear 52. The engine ~poed ln revolution6 per minute (RPM) may also be obta~nod by counting the number of TDC pul6e~ which occur in a speclfied period of time, then multiplying by the appropriate conver~ion con~tant.
, , . , .: ' ' , , .
'3 Computer 56 i~ a conventional digital computer used by those skilled in the art for engine control, and includes the standard element6 of a central proce6sing unit, random access memory (RAM), read only memory (ROM), analog-to-digital converters, input/output circuitry, and clock circuitry. Signals from the previou61y mentioned sen60rs flow over the indicated path6 and æerve as input6 to computer 56.
U6ing these input6, computer 56 performs the appropriate conventional computations to provide an output FUEL SIGNAL to fuel injector 38 and an output SPARK ADVANCE signal to ignition 6ystem 58.
Ignition 6ystem 58 generates a high voltage SPARg 6ignal, which ig applied to 6park plug 36 at the appropriate time, aæ determined by the SPAR~ ADVANCE
6ignal supplied by computer 56 and the po6ition of the engine crankshaft given by the ANGLE and TDC input signal6. Ignition system 58 may include a 6tandard di6tributor or take any other appropriate form in the prior art.
The operation of engine 10 will now be briefly described ba6ed upon the cycle occurring in cylinder 14. During the up6troke, pi6ton 12 moves from it6 lowest po6ition in cylinder 14 toward top dead center.
During the upward movement of piston 12, air inlet port 34 and exhaust port 26 are clo6ed off from the combu~tlon chamber 40, and thereafter, air i6 inducted lnto crankca~e chamber 18 through reed valve 28. Ai r ln combustion chamber 40, above pl6ton 12, i6 mlxed wlth fuel from ln~ector 38 and compressed until 6park plug 36 lgnlte6 the mlxture near the top of the stroke.
As combustlon 18 lnltlated, pl~ton 12 begins the downstroke, decrea~ing the volume of crankca6e ch~mber ', :. , . :, ;-.
203s740 18 and the air inducted therein, due to closure of reedvalve 28. Toward the end of the downstroke, piston 12 uncovers exhaust port 26 to release the combusted fuel, followed by the uncovering of inlet port 34, enabling compressed air within the crankcase chamber 18 to flow through the air transfer passage 30 into cylinder 14.
The cycle begins anew when piston 12 reaches the lowest point in cylinder 14.
In order to effectively control two-stroke engine emission and performance characteristics, it is necessary to know the mass of air available in cylinder 14 at the time of combustion. Once this information is known, the air-fuel ratio can be adjusted to achieve the emission and performance objectives.
Conventional hot wire or hot film sensors can be used to measure the total mass air-flow per cycle in a two-stroke engine; however, these sensors tend to be relatively expensive, fragile, and easily contaminated.
Alternatives have been proposed for eliminating conventional mass air-flow sensors in crankcase scavenged, two-stroke engines, and for providing eetimates of the individual mass air-flow per cylinder.
These techniques are de~cribed in copending Can.
Application Ser. No. 2012431 filed 16 March 1990 and copending Can. Application Ser. No. 2017523 filed 25 May 1990, both of which are a~signed to the assignee of the pre~ent application. In each of these prior applications, the ma~s of air trapped within a crankca~e chamber i5 determined as a function of 30 pressure, volume, and temperature of the air during crankcase compression, prior to tran~fer of air to a cylinder combu~tion chamber. Each of these techniques requires the estimation of correction factors to .
account for incomplete transference of air between crankcase and combustion chambers, and to account for leakage of the transferred air out of the combustion chamber prior to closure of the cylinder exhaust port.
The present invention is directed toward determining the mass or air available for combustion in a cylinder of a crankcase scavenged, two-stroke engine, based upon derived indications of the pressure, volume, and temperature of air within the associated crankcase chamber, but without requiring the correction associated with the incomplete transfer of air between the crankcase and combustion chambers. This is accomplished by first determining the mass of air trapped and undergoing compression in a crankcase chamber, and then determining the residual air mass remaining in the crankcase, just after air is transferred to the associated cylinder through the opened intake port. The mass air actually transferred to the combustion chamber is then determined as a function of the difference between the trapped and residual crankcase air masses. Accordingly, the present invention goes beyond the techniques disclosed in copending Can. Appl. Ser. No. 2012431 filed 16 March 1990 and copending Can. Ser. No. 2017523 filed 25 May 1990, in that, an accurate method for the determination of cylinder mass air is provided, without requiring a correction factor to account for incomplete air traneference between the crankcase and combustion chambers.
The mathematical equations, upon which the lnventlon is based, will not be derived. Since the preseure of the air in crankcase chamber 18 never exceeds the critical preesure, it can be assumed that " ,, ,. ,,: " . .
, ~ t~ 3 ~
the crankca~e air mass at any instant of time is given by the Ideal Gas ~aw:
M ~ PV/RT, (1) where ~, P, v, T, and R are respectively, the mass, pressure, volume, temperature, and gas constant of the crankcase air at a specified time during the engine operating cycle.
A conventional temperature 6ensor could be used to measure crankcase air temperature T, however, engine temperature sensors typically have a long response time compared to the engine cycle time, making it difficult to obtain accurate measurements for crankcase temperature. Thus, an alternative to the actual measurement of crankcase air temperature is de6irable.
As a first approximation, it can be assumed that the crankcase air temperature is equal to the temperature TIN of the air inducted into the engine from the intake manifold. When this approximation is applied to equation (1), an estimate for crankcase air ma66 i 6 given by M -- PV/RTIN, (2) which does not require knowledge of the crankca6e air temperature.
A more accurate estimate for crankca6e air temperature i6 obtained by recognizing that the compression proce66 i8 relatively fa6t compared to the rate of heat transfer. Con6equently, the net heat transfer out of crankcase chamber la i6 negligible, and tho comprc6sion and expan6ion of air in the crankca~e can be con6idered substantially i6entropic.
: ., , : , .
. .
. .
. :,~ .. . . .
.:
~ V 3 ~
Accordingly, the temperature of air in the crankcase can be approximated by r-1 T , TIN(P/PIN) (3) where PIN i6 the pre~sure of air in intake manifold 20, and r represents the ratio of the specific heat of air at constant pressure to the specific heat at constant volume. For air, y is approximately 1.4. Equation (3) is computational cumbersome due to presence of the fractional exponent, and can be further simplified, without introducing significant error, by the linear curve T - TIN[ 0.732 + 0.26B (P/PIN)], which repre6ent6 a best fit of equation ~3) for a range in the pressure ratio (P/PIN) from 0.8 to 1.3.
Substituting the expression for T from eguation (4) into eguation (1) gives M - PV/{R TIN[0-732 + 0-268(P/PIN)]}, (5) for the crankca6e air ma~s at any in6tant of time during the engine operating cycle. Eguation (5) eliminates the need for a crankcase temperature sensor and i8 more accurate than equation (2) in estimating M;
however, knowledge of both the intake air temperature and pre~sure i~ required.
The ma~s of air MT trapped and compressed in crankca8e 1~ can be determined by evaluatinq either of equations (2) or (5), at a time during engine rotation when ~ ~ ~T~ which occurs after the closure of reed valve 28, and after pi6ton 12 pas6es through top dead center, but prior to the openlng of inlet port 34.
Likewi~e, the ma~s of re~idual air MR remaining in the crankca~e, after the transport of air to cylinder 14 is ~ub6tantially completed, can be determined by .. ., ,. ' . - . . . ;. : ,, .
, .. . . .
.. ' . ... ~
evaluating either of equations (2) or (5), at an engine rotation of ~ ~ ~R~ which occurs near the closing of inlet port 34, but prior to the flow of any substantial amount of new air into the crankcase through reed valve 28.
In terms of the trapped and residual air masses described above, an estimate for the air mass M, transferred to combustion chamber 40 from crankcase chamber 18, is given by M - MT ~ MR . (6) However, it has been found that equation (6) tends to slightly over predict engine air flow at low flow rates, apparently due to heat transfer from the crankca~e, which lowers crankcase air density at the lower flow rates. This discrepancy can be minimized by use of the linear equation M + ~(MT MR) (7) to obtain a best fit between actual measured air flow data and predicted air flow based upon the Ideal Gas Law expres6ion of either equation (2) or (5). Linear regression analysis is used to determine the best fit values for a and ~ based on measured and predicted air flow data for a number of different engine speed and load conditions.
In order to perform the computations required to e~timate air mass M according to either of equation6 ~2) or ~5), and equation ~7), computer 56 must be provided with tho proper input signals from engine ~on~ors, from which the required information can be dorivod. In the preferred embodiments of the present invontion, ~n indication of crankcase pressure is provlded by a pres6ure transducer 46, which is dispo6ed within crankca~e chamber lB and develop6 a signal CCP
. - . . . . . . . ...
~3~7~
for input to computer 56. Pressure sensor 46 may be any type of known pressure transducer which is capable of 6ensing the change in air pressure within crankca~e chamber 18.
Manifold temperature sensor 44 provides a MAT
signal indicative of air intake temperature, from which computer 56 can derive a value for TIN as required by equation (2) or by equation (5), if a more accurate estimate for crankcase air temperature is desired.
Likewise, manifold pre6sure sensor 42 provides a MAP
6ignal, which indicates the manifold air pressure, from which computer 56 can derive a value for PIN as required by equation ~5).
Values for the crankcase volume V are required at engine rotational angles ~T and ~R~ for computing the ma~6e6 MT and MR re6pectively, according to either equation (2) or equation (5). The volumes corre6ponding to the rotation6 ~T and ~R are known ba6ed upon the physical design of engine 10, and are 6tored as a lookup table in memory as a function of ~T
and ~R. A6 de6cribed previously, computer 56 derive6 the angular rotation ~ of the engine crank6haft from the ANGLE and TDC 6ignal6 provided by 6ensor6 48 and 50, and continuou61y update6 a 6tored value for ~ in computer 56~
The ma6s M found by u6ing the Ideal Gas Law a6 modified by either equation (2) or (5), and equation (6), represents the m~6~ of air, per cylinder, per cycle flowing into the engine. In order to convert M
into the ma~ of air per cylinder available for combu~tion, the engine trapping efficiency mu6t be ~3~7'~3 known. The mass of air M~ available for cylinder combustion is given by the expression M' - M ~T ' (8) where nT represents the engine trapping efficiency, which i6 the percentage of the mass of air flowing into a cylinder that i~ actually captured in the combu~tion chamber, after closure of the cylinder inlet and exhau6ts ports. The engine trapping efficiency is known to vary with engine 6peed and load.
Conventionally, an engine dynamometer is used to mea6ure trapping efficiency as a function of estimated air flow M, which is related to engine loading, and engine 6peed in RPM. The mea6ured trapping efficiency values are normally stored a6 a lookup table in memory a6 a function of M and RPM.
The pre6ent invention wa6 applied to a 3 cylinder 1.2 liter, two-stroke engine. The cylinder intake port of this engine opened at ~ - 120 after top dead center ~ATDC), and clo6ed at ~ - 240 ATDC. For thi6 particular engine, the best correlation between measured and e6timated air flow occurred when the masses MT and MR were computed at the engine rotational angle6 of ~T ~ 65 ATDC and ~R ~ 255 ATDC, re6pectively.
In one embodiment of the present invention, crankcase temperature wa6 a66umed to equal the intake alr temperature TIN, and the crankca6e air ma66e6 MT
and MR were computod according to the Ideal Gas Law as modlfled ln equatlon ~2). For thi6 embodiment, the bo6t flt of mea~ured and e6timated air flow data wa6 obtalned by ~etting ~ - -0.291 and ~ - 0.840 in oquatlon ~7) for M ln gram6/cylinder/cycle.
~ . ., ,' , . ' ' . ' ~, . .
' ' ' .: '"' ' . ' ' -: ' .
. .
.. .
7 l~ ~
In another embodiment of the present invention, crankcase temperature was estimated by equation (4), and the crankcase air masses MT and MR
were computed according to the Ideal Gas Law as modified in equation (5). For this embodiment, the best fit of equation ~7) to measured and estimated air flow data was obtained using the values of - 0.0571 and . 1.117.
It 6hould be recognized that the optimum values for the above mentioned parameters are engine configuration specific, and different designs will require individual calibration on a dynamometer to determine the optimum angles eT and eR, and correlation coefficients a and ~.
Referring now to FIG. 2, there is shown a 6impllfied flow diagram illustrating a routine executed by computer 56 in estimating the cylinder ma6s air available for combustion, for embodiments of the pre6ent invention. After engine 6tartup, all counters, flag6, regi6ter6, and timers w$th$n computer 56 are $nltiallzed, and 6ystem $nitial values stored in ROM
are entered into ROM designated memory locations in the RAM. After this preliminary initialization, computer 56 continuou61y execute6 a looped main engine control program. The routine illu6trated in FIG. 2 i6 included a6 part of the main control program and i6 executed as computer 56 perform6 $t6 control funct$ons.
The routine i6 entered at point 60, and proceed~ to decision 6tep 62, where the currently ~tored value for crank6haft rotational angle O is comp~red to 0, to determine if the the eng$ne is at top dead center. If the eng$ne i6 at the TDC po6ition, 7 Ll ~
the routine executes step 64, otherwi#e the routine proceeds to decision step 66.
At step 64, computer 56 read~ and stores values for the intake air temperature TIN and pres6ure PIN, by 6ampling input ~ignals MAT and MAP from the re6pective manifold temperature and pres6ure ~en60r6 44 and 42. A6 an alternative to the manifold pres6ure sen60r 44, the pressure PIN can be e~timated by sampling 6ignal CCP from crankcase pressure 6en~0r 46.
When the engine i6 at TDC, the crankcase pressure signal CCP approximately represent6 the pres6ure in the intake manifold 20, because reed valve 28 has not yet closed and piston 12 is not yet compressing air in crankca6e 18. After completinq step 64, the routine proceeds to decision step 66.
At 6tep 66, the current value for the crankshaft rotational angle ~ is compared to ~T~ to determine whether the crankshaft has reached the proper rotation for the calculation of the trapped crankcase ~lr mass MT. If ~ ~ ~T~ the routine executes steps 68 to 74, otherwise, the routine proceeds to deci6ion step 76.
If 6tep 68 i8 executed, computer 56 reads and store6 the crankcase air pres6ure as60ciated with the rotational angle ~T~ by 6ampling the signal CCP
provided by crankcase pre~sure sen60r 46.
Next at step 70, the value for the crankcase volume V(~T), a660ciated with the rotational angle ~T~
~8 looked up in a table 6tored in memory. The routine then proceed~ to ~tep 72.
At step 72, a value for crankca6e temperature is computed. In the embodiment of the invention where crankca~e temperature i~ assumed to be equal to the ;.. . . ..
,,, . . , , ~ , .
,...
. . .~ .
.. . .
intake air temperature, T is merely set equal to TIN.
For the embodiment where crankcase temperature iæ not assumed to equal T~N~ the temperature T i9 computed according to equation (4) using values of TIN, PIN, and P
obtained at steps 64 and 68.
After completing step 72, the routine proceeds to step 74 where an estimate for the crankcase trapped air mass M~ is computed by substituting the values of P, V, and T, found at steps 68 to 72, into the Ideal Gas Law equation (2). Although the preferred embodiments of the present invention use the Ideal Gas Law for determining MT, the invention is not limited to use of that function alone. For example, more accuracy may be obtained by using equation (2) to compute the trapped crankcaee air mass at ~everal rotational positions during crankcaee compres~ion, and then averaging these values to obtain a final estimate for MT.
Alternatively, the trapped crankcase air mass can aleo be determined by integrating crankca~e pressure with respect to the decreaeing volume during crankcaee compression, as ~et forth in the previously mentioned copending Can. Appl. Ser. Nos. 2012431 and 2017523.
After computing and storing the value for M~, the routine proceede to decieion step 76.
At decision etep 76, the current value for the crankchaft rotational angle 0 i8 compared to ORI to determine whether the crankehaft ha~ reached the proper rotation for the calculation of the reeidual crankcase air maeB MR If 0 ~ OR~ the routine proceede to etep 78, 3Q otherwiee, the routine exit~ at etep 94, and return~ to the looped main engine control program.
If ~tep 78 i5 executed, computer 56 reade and etoree the crankcaee air preeeure as~ociated with the , ' ~0~7~
rotational angle ~R~ by 6ampling the signal CCP
provided by crankcase pressure sensor 46.
Next at step 80, the value for the crankcase volume V(~R), associated with the rotational angle ~R~
i8 looked up in a table 6tored in memory. The routine then proceeds to 6tep 82.
At 6tep 72, a value for crankcase temperature i6 computed. In the embodiment of the invention where crankca6e temperature is a6sumed to equal the intake air temperature, T is merely set equal to TIN. For the embodiment where crankcase temperature is not as6umed to equal TIN, the temperature T is computed according to equation (4), u6ing values of TIN, PIN, and P
obtained at 6teps 64 and 78.
After completing 6tep B2, the routine proceeds to 6tep 84 where an e6timate for the residual crankcase air mas6 MR i8 computed by 6ubstituting the value6 of P, V, and T, found at 6teps 78 to 82, into the Ideal Ga6 Law equation (2). A6 previou61y stated, the preferred embodiment6 of the pre6ent invention u6e a 6ingle application of the Ideal Gas Law when determining crankcase air mass; however, the invention i6 not limited to u6e of that function alone. Other function6 ba6ed on crankca6e pre66ure, volume, and temperature may be u6ed; for example, a more accurate estimate for MR may be obtained by averaging the re~ults obt~ined from 6ucces6ive application of the Ideal Gas Law at a number of rotational angle6 occurring near clo6ure of intake port 34, but prior to tho flow of any ~ubstantial amount of new air into crankca~e crankc~se 18 through reed value 28. After computing and 6toring the value for MR, the routine proceeds to ~tep dec~sion step 86.
., , . . :.. `,. : ' , ; .:
,. . : . ..
.:,: ' :. :.
. . .
~Q3~7~
At step 86, values for a and ~, which are to be u6ed in the following 6tep, are retrieved from memory. For the particular engine to which the pre6ent invention wa6 applied, a - -0.291 and ~ . 0.840, for the embodiment where crankca6e air temperature i6 a~6umed to equal TIN. For the embodiment where crankca6e temperature is a66umed to vary a6 in equation (4), ~ - 0.0571 and ~ - 1.117.
Next at 6tep 88, the ma6s of air M tran6ferred from crankca6e 18 to combustion chamber i6 computed based equation (7), a6 a function of the difference between the air mas6es MT, found at step 74, and MR, found in the previou6 6tep 84.
Following 6tep 88, the trapping efficiency of the engine i6 looked up in a table stored in memory, a6 a function of the engine 6peed in RPM and the value of M found in ~tep 88.
At 6tep 92, the final cylinder air ma6s M', which i6 available for combu6tion, i6 computed using eguation (8) with the values of M and nT found at 6tep6 88 and 90. Thi6 value for M' i6 6tored in memory and updated each engine cycle, for u6e in adju6ting engine control parameter~ during the execution of the looped main control program. After 6tep 92 is executed, the routine i6 exited at 6tep 94.
The foregoing de~cription of preferred embodiment6 of the invention i6 for the purpo6e of illu~trating the invention, and i6 not to be con6idered as llmiting or re6tricting the invention, 6ince many modlfic~tion~ may be made by the exerci6e ôf 6kill in the art without departinq from the scope of the invention. In particular, it ~hould be recognized that the invention i6 equally applicable to either air or ' ~ .'' ..:~ :-,,: ' . . , ~ :,~ . . . .
.. , .. - . .. . .
CRAN~CASE 8CAVI~NGED 1~10--STROI~E ENGINE
Background of the Invention Thi6 invention relate6 to the determination of engine mas6 air-flow and more particularly to a method for deriving an indication of the ma6s sf air available for combu6tion within a cylinder of a crankca6e 6cavenged two~6troke engine In a crankca6e 6cavenged two-6troke engine, each individual cylinder ha6 $t6 own 6eparate crankca6e chamber During portion6 of the engine operating cycle, air i6 inducted into each crankcase chamber, compre6sed while the crankca6e chamber i~ decrea6ing in volume, and then tran6ferred to the a660ciated cylinder combu6tion chamber, where it i6 mixed with fuel for ignition In order to effectively control the emi66ion and performance charactoristic6 of 6uch an engine, it i8 nece6sary to know the mas6 of air available at the time of combustion within each cylinder Once thi6 lnformation 16 known, the air-fuel ratio can be ad~usted accordingly to achieved the de6ired emi~6ion and performance ob~ectives Conventional hot wire or hot film 6ensor6 can be u~ed to ea~ure the total air-flow per cycle, in a two-~troke englne, however, these ~ensors tend to be rel~tlvely xpenslve, fraglle, and easlly contamlnated by dlrt ln the ~lr flow Altern~tlves have been propo~-d for llmlnatlng convontlonal mass air-flow -n~ors ln cr~nkcase ~cavenged, two-~troke engines, and for estlmatlng the lndivldual ma~8 alr-flow per , ': ., .
., , ~ .
cylinder. These techniques are described in copending Can. Application Ser. No. 2012431 filed 16 March 1990, and copending Can. Application Ser. No. 2017523 filed 25 May 1990, assigned to the assignee of this application.
In each case, the mass of air trapped within a crankcase chamber is determined as a function of pressure, volume, and temperature of the air during crankcase compression, prior to the transfer of air to a cylinder combustion chamber. Each technique requires correction factors to account for incomplete transference of air between crankca~e and combustion chambers, and to account for leakage of the transferred air out of the combustion chamber prior to cylinder exhaust port closure.
Summary of the Invention The present invention is directed toward determining the mase of air available for combustion in a cylinder of a crankcase scavenged, two-stroke engine, based upon derived indication~ of the pressure, volume, and temperature of air within the associated crankcase chamber, without requiring a correction for the incomplete transfer of air between the crankcase and combu~tion chamber~. Thi~ i8 accompli~hed by first determining the ma~s of air Mk trapped while undergoing compre~sion in a crankcase chamber, and then determining the residual air ma~s MR remaining in the crankca~e, just after the transfer of air to the combustion chamber. The ma~s of air actually transferred to the combuetion chamber i~ then determined directly as a function of the difference ~M~-M~) between the trapped and residual crankca~e air ma~ses. Accordingly, a correction to account for incomplete air tran~ference between crankcase and ''' ' ' ' ' ' ' ' . ' ' ' 203~7~
combustion chambers is not required. Thus, an important feature of the present invention is that combustion mass air can be accurately determined u~ing only a single correction to account for that amount of air which leaks from the cylinder combustion chamber prior to exhaust port closure.
In accordance with the principle of the invention, air mass within a crankcase, both during crankca6e compres~ion and after the transfer of air to the associated combustion chamber, i~ preferably determined according to the Ideal Gas Law, M - PV/~T, where M, P, V, T, and R, are respectively the mass, pressure, volume, temperature, and gas constant for air within the crankcase, determined at the appropriate time6 during the engine operating cycle. Consequently, crankca6e chamber mass air is computed using a relatively 6imple algebraic relationship requiring low computational overhead in a conventional microproce6sor ba~ed engine control 6ystem.
Further, in the preferred embodiments of the present invention the mass of air transferred to a combustion chamber is equated to the expre6sion a +
~MT ~ M~), a predetermined linear function of the difference between the trapped and residual crankcase alr ma~es. Accordingly, improved accuracy i6 achieved when predicting the tran6ferred air ma6s because values for the con~tant6 a and ~ are selected to corre6pond to a be6t flt llne, which relate6 measured and calculated alr flow data obtained under dlfferent engine operating condltions.
Addltlonally, the present invention provides for derlving a required indication of crankcase air temperature a6 a functlon of the temperature of air , ~03~7~
inducted into the engine. This is accomplished by either assuming that the crankcase air temperature is equal to the intake temperature, or a more accurate functional relationship between the crankcase and intake air temperatures can be used, by assuming that the expansion and compression of crankcase air behaves i6entropically. This i6 a 6ignificant feature since engine temperature 6ensors typically have long lag time6 relative to engine cycle time. As a result, intake air temperature, which is generally slowly varying, can be measured more accurately than crankcase air temperature, which varies rapidly over an engine cycle. Also, means for measuring intake air temperature already exists in most typical engine control sy6tems. Consequently, by deriving crankcaEe air temperature as a function of air intake temperature, the invention generally does not require an additional crankcase temperature sen60r to function properly.
According to another aspect of the invention, crankcase volume is derived a6 a predetermined function of the engine cycle position. Preferably, the volume within a crankcase chamber at a given time is defined by the angular rotation of the engine crankshaft as measured by means already existing in a typical engine control system.
A6 contemplated by another a6pect of the lnvention, the pres6ure of air within a crankcase chamber is preferably derived from a conventional pressure 6ensor, dispo~ed within the crankcase chamber.
As a re6ult, the invention require6 only the addition of a relatively inexpensive pres6ure tran6ducer to a ' .
3 ~ L~
conventional computer engine control ~ystem to enable the determination of the cylinder mass air flow.
According to still another aspect of the invention, the value for the air ma6s transferred from a crankcase chamber to its associated cylinder i~
corrected to account for the amount of air which leak~
out of the cylinder prior to closure of the exhaust port. Thu6, an accurate e6timate for the mass air available for cylinder combustion is achieved.
These and other aspects and advantages of the invention may be best understood by reference to the following detailed description of the preferred embodiments when considered in conjunction with the accompanying drawings.
Descr~tion of the Drawings FIG. 1 is a ~chematic diagram of one cylinder of a crankcase scavenged two-stroke engine and control 6ystem therefore, that includes the system for estimating the mass of air available for combustion in accordance with the principles of this invention; and FIG. 2 i6 a flow diagram representing lnstructions in the routine executed by the computer in FIG. 1, when determining the mas6 of air available for combustion in accordance with the principles of thi~
invention.
Detailed DeE_rlptlon of the Preferred Embodiments Referring to FIG. 1, there is shown schematlcally a crankcase scavenged two-~troke engine, generally de8ignated as 10, with a portion of the englne exterlor cut away, expo~lng cylinder 14. Piston 12 re~ides within the wall of cylinder 14, with rod 16 connecting plston 12 to a rotatable crank6haft, not shown, but dl~posed wlthln crankca6e chamber 18.
, .
~ ~ ' ~35~
Connected to engine 10 is an air intake manifold 20 with a throttle 22, and an exhaust manifold 24.
Cylinder 14 communicates with exhau6t manifold 24 through exhaust port 24 in the wall of cylinder 14.
Intake manifold 20 communicate6 with cylinder 14 and crankca6e chamber 18 through a reed valve checking mechanism 28, which opens into a common air tran6fer pa6sage 30 linking crankcase port 32 with inlet port 34 in the wall of cylinder 14. Cylinder 14 i6 provided with a 6park plug 36 and an electric solenoid driven fuel injector 38 projecting into combustion chamber 40.
A6sociated with engine 10 are variou6 conventional 6en60r6 known to the art, which provide typical ~ignal6 related to engine control. Located within the air intake manifold 20 are a pre66ure sen60r 42 for mea~uring intake manifold absolute pres6ure ~MAP), and a temperature 6ensor 44 for mea~uring manifold air temperature (MAT). Electromagnetic sengors 48 and 50 provide pul~ed ~ignal6 indicative of crankshaft rotational position (ANGLE) and the top dead center po6ition for cylinder 14 tTDC), by re6pectively ~ensing movement of the teeth on ring gear 52 and di6k 54, which are attached to the end of the engine crank6haft. The crank6haft rotational angle ~ from top dead center in cylinder 14 can be obtained by counting the number of pul~e6 occurring in the ANGLE 6ignal ater the TDC pulse, then multiplying that count by the angular spacing of teeth on rlng gear 52. The engine ~poed ln revolution6 per minute (RPM) may also be obta~nod by counting the number of TDC pul6e~ which occur in a speclfied period of time, then multiplying by the appropriate conver~ion con~tant.
, , . , .: ' ' , , .
'3 Computer 56 i~ a conventional digital computer used by those skilled in the art for engine control, and includes the standard element6 of a central proce6sing unit, random access memory (RAM), read only memory (ROM), analog-to-digital converters, input/output circuitry, and clock circuitry. Signals from the previou61y mentioned sen60rs flow over the indicated path6 and æerve as input6 to computer 56.
U6ing these input6, computer 56 performs the appropriate conventional computations to provide an output FUEL SIGNAL to fuel injector 38 and an output SPARK ADVANCE signal to ignition 6ystem 58.
Ignition 6ystem 58 generates a high voltage SPARg 6ignal, which ig applied to 6park plug 36 at the appropriate time, aæ determined by the SPAR~ ADVANCE
6ignal supplied by computer 56 and the po6ition of the engine crankshaft given by the ANGLE and TDC input signal6. Ignition system 58 may include a 6tandard di6tributor or take any other appropriate form in the prior art.
The operation of engine 10 will now be briefly described ba6ed upon the cycle occurring in cylinder 14. During the up6troke, pi6ton 12 moves from it6 lowest po6ition in cylinder 14 toward top dead center.
During the upward movement of piston 12, air inlet port 34 and exhaust port 26 are clo6ed off from the combu~tlon chamber 40, and thereafter, air i6 inducted lnto crankca~e chamber 18 through reed valve 28. Ai r ln combustion chamber 40, above pl6ton 12, i6 mlxed wlth fuel from ln~ector 38 and compressed until 6park plug 36 lgnlte6 the mlxture near the top of the stroke.
As combustlon 18 lnltlated, pl~ton 12 begins the downstroke, decrea~ing the volume of crankca6e ch~mber ', :. , . :, ;-.
203s740 18 and the air inducted therein, due to closure of reedvalve 28. Toward the end of the downstroke, piston 12 uncovers exhaust port 26 to release the combusted fuel, followed by the uncovering of inlet port 34, enabling compressed air within the crankcase chamber 18 to flow through the air transfer passage 30 into cylinder 14.
The cycle begins anew when piston 12 reaches the lowest point in cylinder 14.
In order to effectively control two-stroke engine emission and performance characteristics, it is necessary to know the mass of air available in cylinder 14 at the time of combustion. Once this information is known, the air-fuel ratio can be adjusted to achieve the emission and performance objectives.
Conventional hot wire or hot film sensors can be used to measure the total mass air-flow per cycle in a two-stroke engine; however, these sensors tend to be relatively expensive, fragile, and easily contaminated.
Alternatives have been proposed for eliminating conventional mass air-flow sensors in crankcase scavenged, two-stroke engines, and for providing eetimates of the individual mass air-flow per cylinder.
These techniques are de~cribed in copending Can.
Application Ser. No. 2012431 filed 16 March 1990 and copending Can. Application Ser. No. 2017523 filed 25 May 1990, both of which are a~signed to the assignee of the pre~ent application. In each of these prior applications, the ma~s of air trapped within a crankca~e chamber i5 determined as a function of 30 pressure, volume, and temperature of the air during crankcase compression, prior to tran~fer of air to a cylinder combu~tion chamber. Each of these techniques requires the estimation of correction factors to .
account for incomplete transference of air between crankcase and combustion chambers, and to account for leakage of the transferred air out of the combustion chamber prior to closure of the cylinder exhaust port.
The present invention is directed toward determining the mass or air available for combustion in a cylinder of a crankcase scavenged, two-stroke engine, based upon derived indications of the pressure, volume, and temperature of air within the associated crankcase chamber, but without requiring the correction associated with the incomplete transfer of air between the crankcase and combustion chambers. This is accomplished by first determining the mass of air trapped and undergoing compression in a crankcase chamber, and then determining the residual air mass remaining in the crankcase, just after air is transferred to the associated cylinder through the opened intake port. The mass air actually transferred to the combustion chamber is then determined as a function of the difference between the trapped and residual crankcase air masses. Accordingly, the present invention goes beyond the techniques disclosed in copending Can. Appl. Ser. No. 2012431 filed 16 March 1990 and copending Can. Ser. No. 2017523 filed 25 May 1990, in that, an accurate method for the determination of cylinder mass air is provided, without requiring a correction factor to account for incomplete air traneference between the crankcase and combustion chambers.
The mathematical equations, upon which the lnventlon is based, will not be derived. Since the preseure of the air in crankcase chamber 18 never exceeds the critical preesure, it can be assumed that " ,, ,. ,,: " . .
, ~ t~ 3 ~
the crankca~e air mass at any instant of time is given by the Ideal Gas ~aw:
M ~ PV/RT, (1) where ~, P, v, T, and R are respectively, the mass, pressure, volume, temperature, and gas constant of the crankcase air at a specified time during the engine operating cycle.
A conventional temperature 6ensor could be used to measure crankcase air temperature T, however, engine temperature sensors typically have a long response time compared to the engine cycle time, making it difficult to obtain accurate measurements for crankcase temperature. Thus, an alternative to the actual measurement of crankcase air temperature is de6irable.
As a first approximation, it can be assumed that the crankcase air temperature is equal to the temperature TIN of the air inducted into the engine from the intake manifold. When this approximation is applied to equation (1), an estimate for crankcase air ma66 i 6 given by M -- PV/RTIN, (2) which does not require knowledge of the crankca6e air temperature.
A more accurate estimate for crankca6e air temperature i6 obtained by recognizing that the compression proce66 i8 relatively fa6t compared to the rate of heat transfer. Con6equently, the net heat transfer out of crankcase chamber la i6 negligible, and tho comprc6sion and expan6ion of air in the crankca~e can be con6idered substantially i6entropic.
: ., , : , .
. .
. .
. :,~ .. . . .
.:
~ V 3 ~
Accordingly, the temperature of air in the crankcase can be approximated by r-1 T , TIN(P/PIN) (3) where PIN i6 the pre~sure of air in intake manifold 20, and r represents the ratio of the specific heat of air at constant pressure to the specific heat at constant volume. For air, y is approximately 1.4. Equation (3) is computational cumbersome due to presence of the fractional exponent, and can be further simplified, without introducing significant error, by the linear curve T - TIN[ 0.732 + 0.26B (P/PIN)], which repre6ent6 a best fit of equation ~3) for a range in the pressure ratio (P/PIN) from 0.8 to 1.3.
Substituting the expression for T from eguation (4) into eguation (1) gives M - PV/{R TIN[0-732 + 0-268(P/PIN)]}, (5) for the crankca6e air ma~s at any in6tant of time during the engine operating cycle. Eguation (5) eliminates the need for a crankcase temperature sensor and i8 more accurate than equation (2) in estimating M;
however, knowledge of both the intake air temperature and pre~sure i~ required.
The ma~s of air MT trapped and compressed in crankca8e 1~ can be determined by evaluatinq either of equations (2) or (5), at a time during engine rotation when ~ ~ ~T~ which occurs after the closure of reed valve 28, and after pi6ton 12 pas6es through top dead center, but prior to the openlng of inlet port 34.
Likewi~e, the ma~s of re~idual air MR remaining in the crankca~e, after the transport of air to cylinder 14 is ~ub6tantially completed, can be determined by .. ., ,. ' . - . . . ;. : ,, .
, .. . . .
.. ' . ... ~
evaluating either of equations (2) or (5), at an engine rotation of ~ ~ ~R~ which occurs near the closing of inlet port 34, but prior to the flow of any substantial amount of new air into the crankcase through reed valve 28.
In terms of the trapped and residual air masses described above, an estimate for the air mass M, transferred to combustion chamber 40 from crankcase chamber 18, is given by M - MT ~ MR . (6) However, it has been found that equation (6) tends to slightly over predict engine air flow at low flow rates, apparently due to heat transfer from the crankca~e, which lowers crankcase air density at the lower flow rates. This discrepancy can be minimized by use of the linear equation M + ~(MT MR) (7) to obtain a best fit between actual measured air flow data and predicted air flow based upon the Ideal Gas Law expres6ion of either equation (2) or (5). Linear regression analysis is used to determine the best fit values for a and ~ based on measured and predicted air flow data for a number of different engine speed and load conditions.
In order to perform the computations required to e~timate air mass M according to either of equation6 ~2) or ~5), and equation ~7), computer 56 must be provided with tho proper input signals from engine ~on~ors, from which the required information can be dorivod. In the preferred embodiments of the present invontion, ~n indication of crankcase pressure is provlded by a pres6ure transducer 46, which is dispo6ed within crankca~e chamber lB and develop6 a signal CCP
. - . . . . . . . ...
~3~7~
for input to computer 56. Pressure sensor 46 may be any type of known pressure transducer which is capable of 6ensing the change in air pressure within crankca~e chamber 18.
Manifold temperature sensor 44 provides a MAT
signal indicative of air intake temperature, from which computer 56 can derive a value for TIN as required by equation (2) or by equation (5), if a more accurate estimate for crankcase air temperature is desired.
Likewise, manifold pre6sure sensor 42 provides a MAP
6ignal, which indicates the manifold air pressure, from which computer 56 can derive a value for PIN as required by equation ~5).
Values for the crankcase volume V are required at engine rotational angles ~T and ~R~ for computing the ma~6e6 MT and MR re6pectively, according to either equation (2) or equation (5). The volumes corre6ponding to the rotation6 ~T and ~R are known ba6ed upon the physical design of engine 10, and are 6tored as a lookup table in memory as a function of ~T
and ~R. A6 de6cribed previously, computer 56 derive6 the angular rotation ~ of the engine crank6haft from the ANGLE and TDC 6ignal6 provided by 6ensor6 48 and 50, and continuou61y update6 a 6tored value for ~ in computer 56~
The ma6s M found by u6ing the Ideal Gas Law a6 modified by either equation (2) or (5), and equation (6), represents the m~6~ of air, per cylinder, per cycle flowing into the engine. In order to convert M
into the ma~ of air per cylinder available for combu~tion, the engine trapping efficiency mu6t be ~3~7'~3 known. The mass of air M~ available for cylinder combustion is given by the expression M' - M ~T ' (8) where nT represents the engine trapping efficiency, which i6 the percentage of the mass of air flowing into a cylinder that i~ actually captured in the combu~tion chamber, after closure of the cylinder inlet and exhau6ts ports. The engine trapping efficiency is known to vary with engine 6peed and load.
Conventionally, an engine dynamometer is used to mea6ure trapping efficiency as a function of estimated air flow M, which is related to engine loading, and engine 6peed in RPM. The mea6ured trapping efficiency values are normally stored a6 a lookup table in memory a6 a function of M and RPM.
The pre6ent invention wa6 applied to a 3 cylinder 1.2 liter, two-stroke engine. The cylinder intake port of this engine opened at ~ - 120 after top dead center ~ATDC), and clo6ed at ~ - 240 ATDC. For thi6 particular engine, the best correlation between measured and e6timated air flow occurred when the masses MT and MR were computed at the engine rotational angle6 of ~T ~ 65 ATDC and ~R ~ 255 ATDC, re6pectively.
In one embodiment of the present invention, crankcase temperature wa6 a66umed to equal the intake alr temperature TIN, and the crankca6e air ma66e6 MT
and MR were computod according to the Ideal Gas Law as modlfled ln equatlon ~2). For thi6 embodiment, the bo6t flt of mea~ured and e6timated air flow data wa6 obtalned by ~etting ~ - -0.291 and ~ - 0.840 in oquatlon ~7) for M ln gram6/cylinder/cycle.
~ . ., ,' , . ' ' . ' ~, . .
' ' ' .: '"' ' . ' ' -: ' .
. .
.. .
7 l~ ~
In another embodiment of the present invention, crankcase temperature was estimated by equation (4), and the crankcase air masses MT and MR
were computed according to the Ideal Gas Law as modified in equation (5). For this embodiment, the best fit of equation ~7) to measured and estimated air flow data was obtained using the values of - 0.0571 and . 1.117.
It 6hould be recognized that the optimum values for the above mentioned parameters are engine configuration specific, and different designs will require individual calibration on a dynamometer to determine the optimum angles eT and eR, and correlation coefficients a and ~.
Referring now to FIG. 2, there is shown a 6impllfied flow diagram illustrating a routine executed by computer 56 in estimating the cylinder ma6s air available for combustion, for embodiments of the pre6ent invention. After engine 6tartup, all counters, flag6, regi6ter6, and timers w$th$n computer 56 are $nltiallzed, and 6ystem $nitial values stored in ROM
are entered into ROM designated memory locations in the RAM. After this preliminary initialization, computer 56 continuou61y execute6 a looped main engine control program. The routine illu6trated in FIG. 2 i6 included a6 part of the main control program and i6 executed as computer 56 perform6 $t6 control funct$ons.
The routine i6 entered at point 60, and proceed~ to decision 6tep 62, where the currently ~tored value for crank6haft rotational angle O is comp~red to 0, to determine if the the eng$ne is at top dead center. If the eng$ne i6 at the TDC po6ition, 7 Ll ~
the routine executes step 64, otherwi#e the routine proceeds to decision step 66.
At step 64, computer 56 read~ and stores values for the intake air temperature TIN and pres6ure PIN, by 6ampling input ~ignals MAT and MAP from the re6pective manifold temperature and pres6ure ~en60r6 44 and 42. A6 an alternative to the manifold pres6ure sen60r 44, the pressure PIN can be e~timated by sampling 6ignal CCP from crankcase pressure 6en~0r 46.
When the engine i6 at TDC, the crankcase pressure signal CCP approximately represent6 the pres6ure in the intake manifold 20, because reed valve 28 has not yet closed and piston 12 is not yet compressing air in crankca6e 18. After completinq step 64, the routine proceeds to decision step 66.
At 6tep 66, the current value for the crankshaft rotational angle ~ is compared to ~T~ to determine whether the crankshaft has reached the proper rotation for the calculation of the trapped crankcase ~lr mass MT. If ~ ~ ~T~ the routine executes steps 68 to 74, otherwise, the routine proceeds to deci6ion step 76.
If 6tep 68 i8 executed, computer 56 reads and store6 the crankcase air pres6ure as60ciated with the rotational angle ~T~ by 6ampling the signal CCP
provided by crankcase pre~sure sen60r 46.
Next at step 70, the value for the crankcase volume V(~T), a660ciated with the rotational angle ~T~
~8 looked up in a table 6tored in memory. The routine then proceed~ to ~tep 72.
At step 72, a value for crankca6e temperature is computed. In the embodiment of the invention where crankca~e temperature i~ assumed to be equal to the ;.. . . ..
,,, . . , , ~ , .
,...
. . .~ .
.. . .
intake air temperature, T is merely set equal to TIN.
For the embodiment where crankcase temperature iæ not assumed to equal T~N~ the temperature T i9 computed according to equation (4) using values of TIN, PIN, and P
obtained at steps 64 and 68.
After completing step 72, the routine proceeds to step 74 where an estimate for the crankcase trapped air mass M~ is computed by substituting the values of P, V, and T, found at steps 68 to 72, into the Ideal Gas Law equation (2). Although the preferred embodiments of the present invention use the Ideal Gas Law for determining MT, the invention is not limited to use of that function alone. For example, more accuracy may be obtained by using equation (2) to compute the trapped crankcaee air mass at ~everal rotational positions during crankcaee compres~ion, and then averaging these values to obtain a final estimate for MT.
Alternatively, the trapped crankcase air mass can aleo be determined by integrating crankca~e pressure with respect to the decreaeing volume during crankcaee compression, as ~et forth in the previously mentioned copending Can. Appl. Ser. Nos. 2012431 and 2017523.
After computing and storing the value for M~, the routine proceede to decieion step 76.
At decision etep 76, the current value for the crankchaft rotational angle 0 i8 compared to ORI to determine whether the crankehaft ha~ reached the proper rotation for the calculation of the reeidual crankcase air maeB MR If 0 ~ OR~ the routine proceede to etep 78, 3Q otherwiee, the routine exit~ at etep 94, and return~ to the looped main engine control program.
If ~tep 78 i5 executed, computer 56 reade and etoree the crankcaee air preeeure as~ociated with the , ' ~0~7~
rotational angle ~R~ by 6ampling the signal CCP
provided by crankcase pressure sensor 46.
Next at step 80, the value for the crankcase volume V(~R), associated with the rotational angle ~R~
i8 looked up in a table 6tored in memory. The routine then proceeds to 6tep 82.
At 6tep 72, a value for crankcase temperature i6 computed. In the embodiment of the invention where crankca6e temperature is a6sumed to equal the intake air temperature, T is merely set equal to TIN. For the embodiment where crankcase temperature is not as6umed to equal TIN, the temperature T is computed according to equation (4), u6ing values of TIN, PIN, and P
obtained at 6teps 64 and 78.
After completing 6tep B2, the routine proceeds to 6tep 84 where an e6timate for the residual crankcase air mas6 MR i8 computed by 6ubstituting the value6 of P, V, and T, found at 6teps 78 to 82, into the Ideal Ga6 Law equation (2). A6 previou61y stated, the preferred embodiment6 of the pre6ent invention u6e a 6ingle application of the Ideal Gas Law when determining crankcase air mass; however, the invention i6 not limited to u6e of that function alone. Other function6 ba6ed on crankca6e pre66ure, volume, and temperature may be u6ed; for example, a more accurate estimate for MR may be obtained by averaging the re~ults obt~ined from 6ucces6ive application of the Ideal Gas Law at a number of rotational angle6 occurring near clo6ure of intake port 34, but prior to tho flow of any ~ubstantial amount of new air into crankca~e crankc~se 18 through reed value 28. After computing and 6toring the value for MR, the routine proceeds to ~tep dec~sion step 86.
., , . . :.. `,. : ' , ; .:
,. . : . ..
.:,: ' :. :.
. . .
~Q3~7~
At step 86, values for a and ~, which are to be u6ed in the following 6tep, are retrieved from memory. For the particular engine to which the pre6ent invention wa6 applied, a - -0.291 and ~ . 0.840, for the embodiment where crankca6e air temperature i6 a~6umed to equal TIN. For the embodiment where crankca6e temperature is a66umed to vary a6 in equation (4), ~ - 0.0571 and ~ - 1.117.
Next at 6tep 88, the ma6s of air M tran6ferred from crankca6e 18 to combustion chamber i6 computed based equation (7), a6 a function of the difference between the air mas6es MT, found at step 74, and MR, found in the previou6 6tep 84.
Following 6tep 88, the trapping efficiency of the engine i6 looked up in a table stored in memory, a6 a function of the engine 6peed in RPM and the value of M found in ~tep 88.
At 6tep 92, the final cylinder air ma6s M', which i6 available for combu6tion, i6 computed using eguation (8) with the values of M and nT found at 6tep6 88 and 90. Thi6 value for M' i6 6tored in memory and updated each engine cycle, for u6e in adju6ting engine control parameter~ during the execution of the looped main control program. After 6tep 92 is executed, the routine i6 exited at 6tep 94.
The foregoing de~cription of preferred embodiment6 of the invention i6 for the purpo6e of illu~trating the invention, and i6 not to be con6idered as llmiting or re6tricting the invention, 6ince many modlfic~tion~ may be made by the exerci6e ôf 6kill in the art without departinq from the scope of the invention. In particular, it ~hould be recognized that the invention i6 equally applicable to either air or ' ~ .'' ..:~ :-,,: ' . . , ~ :,~ . . . .
.. , .. - . .. . .
2~3~7'~0 fuel based two-stroke engine control systems, where either fuel delivery or engine intake air is respectively regulated based upon the estimated cylinder mass air available for combustion.
. ......... .
'' . ~ '. ' .
.
. ......... .
'' . ~ '. ' .
.
Claims (14)
1. In a crankcase scavenged two-stroke engine characterized by an operating cycle including portions during which air is inducted into a crankcase chamber, is thereafter trapped and compressed within the shrinking volume of the crankcase chamber, and is then transferred to a combustion chamber; a method for determining the mass of air transferred to the combustion chamber during the engine cycle, comprising the steps of:
deriving indications of pressure P, volume V, and temperature T, of air within the crankcase chamber during the engine operating cycle;
determining mass of air MT trapped in the crankcase chamber from indicated values of pressure P, volume V, and temperature T derived during that portion of the operating cycle when air is trapped and compressed within the crankcase;
determining a residual mass of air MR
remaining in the crankcase chamber from indicated values of pressure P, volume V, and temperature T derived during that portion of the operating cycle after the transfer of air to the combustion chamber is substantially completed; and estimating a mass of air M transferred to the combustion by chamber as a function of the difference between the mass of air MT trapped within the crankcase chamber and the mass of air MR remaining within the crankcase chamber.
deriving indications of pressure P, volume V, and temperature T, of air within the crankcase chamber during the engine operating cycle;
determining mass of air MT trapped in the crankcase chamber from indicated values of pressure P, volume V, and temperature T derived during that portion of the operating cycle when air is trapped and compressed within the crankcase;
determining a residual mass of air MR
remaining in the crankcase chamber from indicated values of pressure P, volume V, and temperature T derived during that portion of the operating cycle after the transfer of air to the combustion chamber is substantially completed; and estimating a mass of air M transferred to the combustion by chamber as a function of the difference between the mass of air MT trapped within the crankcase chamber and the mass of air MR remaining within the crankcase chamber.
2. The method in claim 1, wherein the mass of air MT trapped in the crankcase is determined in accordance with the Ideal Gas Law, such that MT =
PV/RT, where R is the gas constant for air.
PV/RT, where R is the gas constant for air.
3. The method in claim 1, wherein the mass of air MR remaining in the crankcase is determined in accordance with the Ideal Gas Law, such that MR =
PV/RT, where R is the gas constant for air.
PV/RT, where R is the gas constant for air.
4. The method in claim 1, wherein the mass of air M transferred to the combustion chamber is determined in accordance with the expression M = .alpha. +
.beta.(MT - MR), where .alpha. and .beta. are predetermined constants.
.beta.(MT - MR), where .alpha. and .beta. are predetermined constants.
5. The method in claim 1, wherein the crankcase air temperature T is derived as a function of the temperature of air inducted into the engine.
6. The method of claim 1, wherein the crankcase volume V is derived as a function of the engine cycle position.
7. The method of claim 1, wherein the crankcase pressure P is derived from a pressure sensor located within the crankcase of the engine.
8. In a crankcase scavenged two-stroke engine characterized by an operating cycle including portions during which air is inducted into a crankcase chamber, is thereafter trapped and compressed within the shrinking volume of the crankcase chamber, and is then transferred to and trapped in a combustion chamber; a method for determining the mass of air trapped in the combustion chamber during the engine cycle, comprising the steps of:
deriving indications of pressure P, volume V, and temperature T, of air within the crankcase chamber during the engine operating cycle;
determining mass of air MT trapped in the crankcase chamber from indicated values of pressure P, volume V, and temperature T derived during that portion of the operating cycle when air is trapped and compressed within the crankcase;
determining a residual mass of air MR
remaining in the crankcase chamber from indicated values of pressure P, volume V, and temperature T
derived during that portion of the operating cycle after the transfer of air to the combustion chamber is substantially completed;
estimating a mass of air M transferred to the combustion by chamber as a function of the difference between the mass of air MS trapped within the crankcase chamber and the mass of air MR remaining within the crankcase chamber;
determining a trapping efficiency value representing the percentage of the transferred mass of air M, which is trapped in the combustion chamber; and adjusting the transferred mass of air M in accord with the determined trapping efficiency value to provide a measure of the air mass trapped in the combustion chamber.
deriving indications of pressure P, volume V, and temperature T, of air within the crankcase chamber during the engine operating cycle;
determining mass of air MT trapped in the crankcase chamber from indicated values of pressure P, volume V, and temperature T derived during that portion of the operating cycle when air is trapped and compressed within the crankcase;
determining a residual mass of air MR
remaining in the crankcase chamber from indicated values of pressure P, volume V, and temperature T
derived during that portion of the operating cycle after the transfer of air to the combustion chamber is substantially completed;
estimating a mass of air M transferred to the combustion by chamber as a function of the difference between the mass of air MS trapped within the crankcase chamber and the mass of air MR remaining within the crankcase chamber;
determining a trapping efficiency value representing the percentage of the transferred mass of air M, which is trapped in the combustion chamber; and adjusting the transferred mass of air M in accord with the determined trapping efficiency value to provide a measure of the air mass trapped in the combustion chamber.
9. The method in claim 8, wherein the mass of air MT trapped in the crankcase is determined in accordance with the Ideal Gas Law, such that MT =
PV/RT, where R is the gas constant for air.
PV/RT, where R is the gas constant for air.
10. The method in claim 8, wherein the mass of air MR remaining in the crankcase is determined in accordance with the Ideal Gas Law, such that MR =
PV/RT, where R is the gas constant for air.
PV/RT, where R is the gas constant for air.
11. The method in claim 8, wherein the mass of air M transferred to the combustion chamber is determined in accordance with the expression M = .alpha. +
.beta.(MT - MR), where .alpha. and .beta. are predetermined constants.
.beta.(MT - MR), where .alpha. and .beta. are predetermined constants.
12. The method in claim 8, wherein the crankcase air temperature T is derived as a function of the temperature of air inducted into the engine.
13. The method of claim 8, wherein the crankcase volume V is derived as a function of the engine cycle position.
14. The method of claim 8, wherein the crankcase pressure P is derived from a pressure sensor located within the crankcase of the engine.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/514,997 US4995258A (en) | 1990-04-26 | 1990-04-26 | Method for determining air mass in a crankcase scavenged two-stroke engine |
| US07/514,997 | 1990-04-26 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2035740A1 CA2035740A1 (en) | 1991-10-27 |
| CA2035740C true CA2035740C (en) | 1994-05-17 |
Family
ID=24049572
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002035740A Expired - Fee Related CA2035740C (en) | 1990-04-26 | 1991-02-05 | Method for determining air mass in a crankcase scavenged two-stroke engine |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4995258A (en) |
| EP (1) | EP0454191B1 (en) |
| JP (1) | JPH079207B2 (en) |
| AU (1) | AU621253B2 (en) |
| CA (1) | CA2035740C (en) |
| DE (1) | DE69100055T2 (en) |
Families Citing this family (29)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4987773A (en) * | 1990-02-23 | 1991-01-29 | General Motors Corporation | Method and means for determining air mass in a crankcase scavenged two-stroke engine |
| JP3133311B2 (en) * | 1990-04-24 | 2001-02-05 | ヤマハ発動機株式会社 | Fuel injection two-stroke engine |
| DE4115032A1 (en) * | 1991-05-08 | 1992-11-12 | Bosch Gmbh Robert | ELECTRONIC SYSTEM IN A MOTOR VEHICLE FOR DETECTING A BAD ROUTE |
| JPH07293297A (en) * | 1994-04-20 | 1995-11-07 | Hitachi Ltd | Fuel control method and apparatus for internal combustion engine, and vehicle using the same |
| US5471400A (en) * | 1994-05-24 | 1995-11-28 | Gas Research Institute | Method for detecting and specifying compressor cylinder leaks |
| US5684245A (en) * | 1995-11-17 | 1997-11-04 | Mks Instruments, Inc. | Apparatus for mass flow measurement of a gas |
| US6009355A (en) | 1997-01-28 | 1999-12-28 | American Calcar Inc. | Multimedia information and control system for automobiles |
| US6148261A (en) * | 1997-06-20 | 2000-11-14 | American Calcar, Inc. | Personal communication system to send and receive voice data positioning information |
| US6275231B1 (en) * | 1997-08-01 | 2001-08-14 | American Calcar Inc. | Centralized control and management system for automobiles |
| US6089082A (en) * | 1998-12-07 | 2000-07-18 | Ford Global Technologies, Inc. | Air estimation system and method |
| DE19908401C2 (en) * | 1999-02-26 | 2001-12-06 | Bosch Gmbh Robert | Method and device for operating an internal combustion engine, in particular a motor vehicle, with a lean fuel / air mixture |
| US7187947B1 (en) | 2000-03-28 | 2007-03-06 | Affinity Labs, Llc | System and method for communicating selected information to an electronic device |
| EP1328420A4 (en) * | 2000-09-21 | 2009-03-04 | American Calcar Inc | TECHNIQUE FOR OPERATING A VEHICLE EFFECTIVELY AND SECURELY |
| US8990367B2 (en) * | 2006-09-29 | 2015-03-24 | Dell Products L.P. | Consistent binding of shared storage across clustered servers |
| CA2463922C (en) | 2001-06-27 | 2013-07-16 | 4 Media, Inc. | Improved media delivery platform |
| US9818136B1 (en) | 2003-02-05 | 2017-11-14 | Steven M. Hoffberg | System and method for determining contingent relevance |
| DE102004058185A1 (en) * | 2004-12-02 | 2006-06-08 | Robert Bosch Gmbh | Internal combustion engine e.g. diesel engine, controlling method for motor vehicle, involves determining gas masses using gas pressures reigning in engine`s cylinders and comparing values formed from masses and formed independent of masses |
| US8874477B2 (en) | 2005-10-04 | 2014-10-28 | Steven Mark Hoffberg | Multifactorial optimization system and method |
| US7536983B2 (en) * | 2006-01-19 | 2009-05-26 | Andreas Stihl Ag & Co. Kg | Internal combustion engine and method for operating an internal combustion engine |
| DE102006060617B4 (en) * | 2006-01-19 | 2019-11-14 | Andreas Stihl Ag & Co. Kg | Method for operating an internal combustion engine |
| US8986253B2 (en) | 2008-01-25 | 2015-03-24 | Tandem Diabetes Care, Inc. | Two chamber pumps and related methods |
| US8408421B2 (en) | 2008-09-16 | 2013-04-02 | Tandem Diabetes Care, Inc. | Flow regulating stopcocks and related methods |
| AU2009293019A1 (en) | 2008-09-19 | 2010-03-25 | Tandem Diabetes Care Inc. | Solute concentration measurement device and related methods |
| CA2769030C (en) | 2009-07-30 | 2016-05-10 | Tandem Diabetes Care, Inc. | Infusion pump system with disposable cartridge having pressure venting and pressure feedback |
| US9180242B2 (en) | 2012-05-17 | 2015-11-10 | Tandem Diabetes Care, Inc. | Methods and devices for multiple fluid transfer |
| US20150275782A1 (en) * | 2012-11-29 | 2015-10-01 | Toyota Jidosha Kabushiki Kaisha | Control device for engine equipped with supercharger |
| US9173998B2 (en) | 2013-03-14 | 2015-11-03 | Tandem Diabetes Care, Inc. | System and method for detecting occlusions in an infusion pump |
| FR3044713B1 (en) * | 2015-12-08 | 2017-12-01 | Continental Automotive France | METHOD AND DEVICE FOR DETERMINING THE FLOW OF AIR ENTERING THE INTAKE MANIFOLD OF A TWO-STROKE ENGINE |
| DE102019212457B4 (en) * | 2019-08-21 | 2021-03-25 | Vitesco Technologies GmbH | Method and device for leakage diagnosis of a crankcase ventilation line of a crankcase ventilation device for an internal combustion engine |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5917371B2 (en) * | 1979-03-16 | 1984-04-20 | 日産自動車株式会社 | flow rate detection device |
| US4404946A (en) * | 1979-09-27 | 1983-09-20 | Ford Motor Company | Method for improving fuel control in an internal combustion engine |
| US4446523A (en) * | 1981-11-13 | 1984-05-01 | General Motors Corporation | Mass air flow meter |
| US4402294A (en) * | 1982-01-28 | 1983-09-06 | General Motors Corporation | Fuel injection system having fuel injector calibration |
| JPS595875A (en) * | 1982-07-01 | 1984-01-12 | Sanshin Ind Co Ltd | Fuel injection device for two-cycle internal-combustion engine |
| US4664090A (en) * | 1985-10-11 | 1987-05-12 | General Motors Corporation | Air flow measuring system for internal combustion engines |
| US4750464A (en) * | 1987-03-12 | 1988-06-14 | Brunswick Corporation | Mass flow fuel injection control system |
| US4750352A (en) * | 1987-08-12 | 1988-06-14 | General Motors Corporation | Mass air flow meter |
| US4788854A (en) * | 1987-12-07 | 1988-12-06 | General Motors Corporation | Method of estimating the fuel/air ratio of an internal combustion engine |
| US4920790A (en) * | 1989-07-10 | 1990-05-01 | General Motors Corporation | Method and means for determining air mass in a crankcase scavenged two-stroke engine |
| US4987773A (en) * | 1990-02-23 | 1991-01-29 | General Motors Corporation | Method and means for determining air mass in a crankcase scavenged two-stroke engine |
-
1990
- 1990-04-26 US US07/514,997 patent/US4995258A/en not_active Expired - Fee Related
-
1991
- 1991-02-05 EP EP91200221A patent/EP0454191B1/en not_active Expired - Lifetime
- 1991-02-05 CA CA002035740A patent/CA2035740C/en not_active Expired - Fee Related
- 1991-02-05 DE DE9191200221T patent/DE69100055T2/en not_active Expired - Fee Related
- 1991-02-08 AU AU70858/91A patent/AU621253B2/en not_active Ceased
- 1991-02-22 JP JP3028920A patent/JPH079207B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| AU7085891A (en) | 1991-12-12 |
| EP0454191A1 (en) | 1991-10-30 |
| EP0454191B1 (en) | 1993-03-31 |
| US4995258A (en) | 1991-02-26 |
| CA2035740A1 (en) | 1991-10-27 |
| DE69100055T2 (en) | 1993-07-08 |
| JPH0544567A (en) | 1993-02-23 |
| JPH079207B2 (en) | 1995-02-01 |
| DE69100055D1 (en) | 1993-05-06 |
| AU621253B2 (en) | 1992-03-05 |
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